i was talking to this guy about my car and he was telling me about how a company in NY had made stainless steel hatches for the 5.0 guys mostly, because of the rust problem.
why? Keep some paint on it, and it won't rust.
I don't have any visible rust on my hatch, and it is 16 years old. I just try to keep a coat of wax, and if I see a little spot of rust, I clean it up, and use touchup before it can get any worse.